Add clarifying comment

ee/app/controllers/ee/clusters/clusters_controller.rb

@@ -51,7 +51,7 @@ module EE
       end
       
       def metrics_dashboard
-        project_for_dashboard = defined?(project) ? project : nil
+        project_for_dashboard = defined?(project) ? project : nil # Project is not defined for group and admin level clusters
         dashboard = ::Gitlab::Metrics::Dashboard::Finder.find(project_for_dashboard, current_user, metrics_dashboard_params)
 
         respond_to do |format|

ee/spec/services/metrics/dashboard/cluster_dashboard_service_spec.rb

@@ -31,7 +31,7 @@ describe Metrics::Dashboard::ClusterDashboardService, :use_clean_rails_memory_st
     context 'when called with a non-system dashboard' do
       let(:dashboard_path) { 'garbage/dashboard/path' }
 
-      # We want to alwaus return the cluster dashboard.
+      # We want to always return the cluster dashboard.
       it_behaves_like 'valid dashboard service response'
     end
   end